1. Field of the Invention
The invention generally relates to an optical lens and a manufacturing method thereof, and more particularly to a liquid crystal optical lens with adjustable refractive power and a manufacturing method thereof, and to a lens apparatus using the liquid crystal optical lens.
2. Description of Related Art
In a common lens system, in a lens apparatus which has an optical zoom function, each of the lens groups located inside the lens apparatus must generate corresponding movements to accommodate changes in a zoom ratio. In a conventional mechanical design of a miniature optical zoom lens, the mechanical design usually requires at least two driving apparatuses. That is, at least two step motors, ultrasonic motors, piezoelectric actuators, and the like are required as the driving source. However, implementing the zoom lens in this manner results in a bulky yet complicated structure, in contrast to a goal of product miniaturization and portability. Moreover, the relative movements of each lens group requires a position sensor and a close-loop controller to implement, which goes against a requirement of consumer products in simplicity and low price.
Moreover, besides using high cost precision driving devices as the motor sources (e.g., stepping motors, ultrasonic motors, piezoelectric actuators) of the lens groups, the focus and zoom structures used in a common lens apparatus further employ a plurality of micro gears, cam wheels, turbines, and the like transmission devices. Therefore, not only are the structural framework more complicated, the assembly steps made more difficult and numerous, the size more bulky and the cost more expensive, but power consumption has also exponentially increased.
Consequently, in order to alleviate the aforementioned issues, an adjustable zoom liquid crystal lens that decreases structural complexity and minimizes bulk for the above-described lens apparatus has become increasingly important. Hereinafter, various related research proposals are described.
In U.S. Pat. No. 7,079,203, the disclosure proposes using a polymer network liquid crystal (PNLC) method to achieve the optical functions of the lenses. However, since the optical functions are not achieved with a single apparatus/module, consumer application is limited due to implementation difficulties.
Moreover, in U.S. Pat. No. 7,042,549, the disclosure proposes using a polymer dispersed liquid crystal (PDLC) method to provide lens functions using liquid crystal droplets. However, the disclosure does not describe a lens scaling module.
In U.S. Pat. No. 7,102,706, the disclosure proposes a method of grouping liquid crystal molecules in a PNLC. Similarly, however, since the optical functions are not achieved with a single apparatus/module, consumer usage is not possible due to implementation difficulties.
Moreover, in U.S. Pat. No. 6,898,021, the disclosure proposes a single tunable LC lens structure, but does not propose using a PNCL type lens function. In addition, the proposed optical system is not a multi-stage liquid crystal lens structure.
In U.S. Pat. No. 6,859,333, the disclosure proposes an apparatus utilizing electric field variations to change the light paths in a liquid crystal lens. However, since the proposed apparatus does not have a module structure, consumer application is still limited due to implementation difficulties.
Similarly, in U.S. Pat. Nos. 5,867,238, 5,976,405, 6,002,383, 6,211,898, 6,452,650, 6,476,887, 6,497,928, 6,665,042, 6,815,016, 6,864,931, 6,897,936, 7,029,728, 7,034,907, 7,038,743 and 7,038,754, the disclosures proposed various methods of using liquid crystal lens, and more specifically, structures including a PNLC mixture and a stop. However, these disclosures do not describe a scaling device or a module structure.